Thermostatic switching device for electric irons



Filed March 14. 1922 Patented Oct. 2, 1923.

UNITED STATES- 1,469,121 PATENT OFFICE.

FRANK im, F ALPINA, IICHIGAN, LBSIGNOB 0F ONE-THIRD T0 HIIBELF, ONE- THIRD TOPbBm A. BUCK! ND ONE-THIRD T0 NELSON I. EDDY, ALL 0I' ALPINA,

IICHIGAN.

l'.IBHEBIOSJ?AI'IG BWITCHTNG DEVICE FOB ELECTRIC IDONE- Applieation illed Harel Il, 1m. lerlal lo. 543,399.

To all whom it may concern: y

Be it known that I, FRANK J ERMIN a citizen of the United States, and a resident of Al ena, in the county of Alpena and State of ichi an, have invented a new and Imroved hermostatic Switching Device for lectric Irons, of which the following is a full, clear, and exact description.

This invention relates to a thermostatic switching device for electric irons,and has particular reference to means whereby the current supplied to and the temperature of the iron may be controlled.

A main object of the invention resides in .the provision of a thermostatically operated switch constructed to open and break the electric circuit at a nedetermined temperature, and means com ined therewith to prevent the switch from being closed a ain until the ironhas cooled by a de nite amount.

Another object resides in the construction of the above mentioned switch in such manner that it may be at any time released manually lwhen desired.

A further object resides in the construction of `a circuit-controllin unit, including a thermostat which is app icable in a very economical manner to anyV suitable t pe of iron with a minimum necessity for altering the structure of the iron.

A still further object resides in the disposition of the parts in such manner that they are substantially enclosed within` the iron and can Vbe aiected only to a minimum degree by outside interference.

Another object resides in the construction of a thermostat which is extremely sensitive to operate quickly and eiciently at the critical temperature to open the circuit.

A further object yresides in the particular construction and 'arrangement of parts which are'hereinafter described and claimed and shown inthe accompanying drawings;

The invention is illustrated in the drawings, of which- Figure 1 is a vertical section through the body portion of the iron showing the currentdcontrolling switch located in theheel of the iron.

Figf isV 'a plan view of the rear rtion of the iron with the cover remoped owing the parte in their closed position. l Fig. 8 is a partial vertical sectional view through the iron, and enlarged, showing the manually operated switch and the thermostatic means for openin it.

Fig. 4 is a plan view o Fig. 3 and also includes a diagram of the essential circuit connection.

The form of the invention shown in the drawings is at'preferred form, although it is understood that modifications in the construction and arra ent of the parts and in the character of e material used may be ado ted without departing from the spirit of t e invention.

One forni in which my invention may be embodied is illustrated in the drawings and comprises an iron having an ironi surface 1 and a body portion 2 within whic an electrical heating medium is disposed in any desired and well known manner. This iron is provided with a cover 3 and a handle 4. The cover, handle, body portion and ironin surface are fastened' together in any `well known manner by means of screws 5 and 6. The rear portion of the body 2 is provided with a vrecess 7, and in this recess there is adapted to be dis osed current-controlling devices whereby t e heating current supplied to the heating element is controlled to any desired degree.

This controlling ap aratus comprises a switch bar 8 having a utton 9 on its end whereby it. may be manuall operated, and a spring 10 tendingD normal y to disengage the switch bar from the s ring contact iingers 11 and 12. The switc bar is not only adapted to be operated manually but is also adapted to be operated by a thermostat or temperature responsive element 13. The switch bar 8, the temperature responsive element 13, and their zo-operating parts,' are connected to and mounted on a switch base 14, preferably, although not necessarily, in the form of a sheetmetal stamp 14 having a cup-shaped depression 15 vto receive the thermostatic element 13, which is shown, and preferably is, in the form of a flat disklike container within which is dismsed, preferably, an 4expansive uid which a definite tem rature beyond which it expands. The ateral faces of the disk, such as 16 and 17 are 'of such thickness that the expension of the Huid within the disk or container 13 will cause a deflection thereof.

This disk-like container 13 is clamped in the recess by reason of the engagement therewith of lingers 18, preferably struck from the metal of the stamping or swltch base. 14. The switch bar S is provided u 1th a base portion 19 adapted in the normal position of the bar to rest on the top surface 1| of the thcrmostatic element lil. The bar is provided with a contact stud 2U extending through the bar and electrically separated therefrom by insulation 21 in the form of an insulated sleeve. This stud is adapted lo bridge the gap between the spring contact fingers 11 and 12. The bar is provided with a notch 22 adapted to engage with a lip 2li formed in the bottom of a slot 2l at the rear of the stamping or switch base 1 4. This stamping atits rear end is also provided with a struck-up finger 2-1 which is adapted to project across the top edge. of the bar to limit the amount to which it can be lifted to an amoxmt just sufficient to permit of *he release ot' the notch 22 from the lip 23. The bar is adapted to ride in this slot so formed. A pm '2:3 engages with the rear wall of the switch base to prevent the switch bar from moving backward more than a determined amount.. The forward end of the bar is tapered as at- 26 nud protrudes through a slot 2T formed in the front wall of the switch base. The position of the front end of the bar when the switch closes is indicated in full lines in Fig. 3. The position of the bar when the switch is open is indicated in dot-and-dash line in this same figure. These two positions will indicate that the forward portion or edge of the bar 8 always engages to some extent in the slot 2T. 'hen the switch is in its closed position. a fulcrum pin is formed at the point 28. for instance, so that when the thermostatic element 13 expands against the base 19 of the bar. the rear end in which the notch 22 is located is lifted 'from engagement with the lip 23. so that the spring 10 will torce the bar hack to the limit of the movement allowed by the pin 25 so that the stud 20 will disengage from the spring fingers 11 and l2. The slot 24 is of ample height to allow the bar S to be disengaged from the lip 23 and to slide far enou h back to open the switch. However, t e switch can he released manually by moving the button or knob 9 with the linger. thus manually disengaging the lip 23 from the notch 22.

'hen the thermostatic element 13. however. is in its expanded condition and the switch has been released, it will be observed that it will be impossible to move the switch hack into closed position becauseV the parts are so coordinated that the switch bar can only be disposed in its closed position when the thermostatic element 1s not in its expanded condition. This element expands only when a predetermined temperature is obtained, and as long as this temperature remains the disk 13 will remain expanded and will not allow the switch to be moved back so that the notch 22 will engage with the lip 23. This provision keeps the switch in the oil' position until the iron is sufficiently cooled below the predetermined temperature, and will keep the switch open even then until it is operated by hand to move itto the closed position.

In Fig. 4 .I show the ordinary terminal posts 29 and 30, a terminal wire 31 connected to the post 29, and a wire 32 connected to the post 30. The wire 31 is connected to one end of a heater element 33, the other end of which is connected to a binding post 34. This binding post is insulatingly supported in any desired'n'ianner on the iron. The other spring finger 12 is connected t0 a similar binding post 35 to which the wire 32 is connected. It is, of course, easily understood that the circuit between the terminal posts and the heating element is bl'oken at the spring contact. lingers 11 and 12. The binding posts 3-1 and 35 are thoroughly insulated from the switch base 1-1 in any suitable manner. They are pre ferably, although not necessarily, supported in this manner from the switch base. It will be seen, therefore, that this switch base or stamping 1-1 supports the thermostatic element, the switch bar, its operating spring, the binding posts and the spring fingers. The supporting of these different elements on the one base makes the insertion of this control device a matter of the insertion of the single unit which can be Separately assembled and put in an iron provided the iron has a recess such as 7 suicient. to receive the unit. After that it is merely a matter of making the proper wire connections between the heater element. the unit and the terminal posts. This unit, including the base plate 14, can be fastened to the body portion of the iron by any suitable means. such as a screw 36. The terminal posts 29 and 30 and the button 9 are protected by sleeve ortions sucli as 3T and 38 in a manner well mown in electric irons so that they cannotbe very readily injured by contact.

What I cla-im is:

1. A thermostatic switching device for electric irons which comprises a current controlling switch, an expansible thermostatic element disposed in association with the switch whereby its expansion willopen the switch at a predetermlned temperature, said thermostatic element being so disposed that when expanded the switch cannot be returned to its closed position.

2. A thermostatic switching device for i` electric irons which comprises a manually operable switch, expansble thermostatic means for opening said switch at a predetermined temperature, the expansion of the :meej-a? 4 to moye' it fopenpstion and barring'-v tion 4.until the thermostatic'elementhas assumed its .normal position.' A

lingers;- a -fslid'able switch bar adapted to' jcuit, Va ,dat disldike container containinggex- .-.pansiyehuid; 'affportion of the bar resting 'normally on 'the disklike container 'when thebar lis in its closed osition, means engaging the switch bar ten ing to move it to its open osition, and means for holding the switch ar in its closed sition, the

expansion of the fluid within t e container causing the release of the means for holding the switch bar whereby it is moved to open position.

4. A current control device for electric irons, which comprises a slidable switch bar, a contact stud thereon, spring circuit fingers Vwith which the stud is adapted to engage to close the circuit when the bar is in its closed position, a switch base oi which said bar is mounted having a slot therein, an ex# pansible temperature-responsive element disposed on the switch base beneath the bar to en age with the bar in its closed position, an y a spring engaging the bar and te'iidin normally to move it toits open position, sai bar having, a notch to engage with a portion of the switch base in said slot to hold the switch bar inits closed position, said switch base having a second slot engaging with the forward end of the switch bar, this engagement causing the front end of the bar to act as a fulcrum when the tem rature-responsive element expands and re eases the switch. 5. A current. control device for electric irons, which comprises a slidable switch bar, a contact stud thereon, spring circuit fingers with which the stud is adapted to engage to close the circuit when the Vbar is in its closed position, a switch base on which said bar is'mounted having a slot therein, an expansible temperature-responsive element disposed on the switch base beneath the bar to engage wlth the bar in its closed position,

ana a spring engaging the bar and tending` normally to move it to its open sition, said bar having a notch to engage with a portion 23; A thermostatic' .switching `device A forl electric' irons which-,comprises spring con-,

ftheswiihtse in said slot fio-hole the switch bar-iii' its 4.closed position, said switch base having as'econ'd slot engaging with the forward 'end `of the switch bar, this e e nient causing the front end-of the bar to act as ayfulcruni when the tem saidswitch'bar havin on its rear end a knob which can' *b emanua the baratfwill.

y engaged to release' rature-responsive element expands and re eases the switch,

' f6. A thermostatic switching device for electric irons which comprises a movable switch bar disposed in the heel of the from the iron to and temperature-responsive means within the iron and engaging with the bar to automatically o n A,the switch whenthe temperature ofY t e iron reaches a predetermined degree.

7. A thermostatic switching device for electric irons which comprises a switch element having a normally closed position, and temperatureresponsive means `engaging with the'switch bar in its closed position, the actuation of the temperature-responsive means whenV the temperature exceeds a certain degree moving the switch from its closed to an open position, said temperature responsive means in its expanded position obstructing the normal path of movement of the switch to its closed osition whereby the switch cannot, be closed) until the temperature has dropped a redetermined amount.

8. A thermostatic switching device for electric irons which comprises a switch element having a normally closed position, temperature-res onsive means engaging with the switch ar in lits closed position, the actuation of the temperature-responsive means when the Vtemperature exceeds a certain degree moving the switch from its closed to an open positionsaid temperature` responsive means in* its expanded position obstructing the normal path of movement of the switch to its closed 'tion whereby the switch cannot be close until the temperature has dropped a predetermined amount, and means on said switch its operation by hand, said last-mentioned means extending suiliciently from the iron to permit of manual en ment.

` I ANK element to permit iron, a knob f on the rear end of the bar and pro'ecting- 

